1. Field of the Invention
The present invention relates to a system and method for locating and using multiple routes to transmit sub-packets of data from a source node to a destination node while preventing intermediate nodes in any single transmission path from intercepting a useful amount of information for malicious purposes. The system and method routes communications between a source node and a destination node via multiple routes, selected in a random fashion. Further protection is achieved by breaking data packets into sub-packets requiring reassembly at the destination node.
2. Description of the Related Art
In recent years, a type of mobile communications network known as an “ad-hoc” network has been developed. In this type of network, each user terminal (hereinafter “mobile node”) is capable of operating as a base station or router for other mobile nodes, thus eliminating the need for a fixed infrastructure of base stations. Accordingly, data packets being sent from a source mobile node to a destination mobile node are typically routed through a number of intermediate mobile nodes before reaching the destination mobile node.
More sophisticated ad-hoc networks are also being developed which, in addition to enabling mobile nodes to communicate with each other as in a conventional ad-hoc network, further enable the mobile nodes to access a fixed network and thus communicate with other types of user terminals, such as those on the public switched telephone network (PSTN) and on other networks such as the Internet.
Details of these types of ad-hoc networks are described in U.S. Pat. No. 7,072,650 B2 entitled “Ad Hoc Peer-to-Peer Mobile Radio Access System Interfaced to the PSTN and Cellular Networks”, granted on Jul. 4, 2006, in U.S. Pat. No. 6,807,165 B2 entitled “Time Division Protocol for an Ad-Hoc, Peer-to-Peer Radio Network Having Coordinating Channel Access to Shared Parallel Data Channels with Separate Reservation Channel”, granted on Oct. 19, 2004, and in U.S. Pat. No. 6,873,839 B2 entitled “Prioritized-Routing for an Ad-Hoc, Peer-to-Peer, Mobile Radio Access System”, granted on Mar. 29, 2005, the entire content of each of said patents being incorporated herein by reference.
As can be appreciated by one skilled in the art, when a node sends packetized data to a destination node, the node typically performs a calculation to determine whether the destination node is contained in its routing table. If the destination node is contained in the node's routing table, the data is transmitted via a path that leads to the destination node. If the destination node is not listed in the node's routing table, then the packet is sent to one or more other nodes which are listed in the node's routing table, and each receiving node then determines if the destination node is listed in their respective routing tables. This process continues until the data packet eventually reaches the destination node.
Routing data packets from node to node however, poses several security concerns. In an ad-hoc network, a node may arbitrarily connect to another node or transition through any number of nodes to communicate with a final destination. However, transmission security concerns often requires the consideration of node security when selecting routing nodes from a routing table. Certain networks, such as the Internet and mobile ad-hoc networks, rely on having multiple diverse routes between a source and a destination for reliability and robustness. In practice, there are multiple acceptable routes between the source and the destination at any given time. Current routing algorithms use a number of metrics to decide what is the best route between the source and the destination, and this route is used until it becomes incapable of meeting the performance criteria. Once this occurs, an alternate route is selected and implemented.
One of the biggest security concerns of a network of this type regards an intermediate node, between the source node and the destination node, which is able to detect data within routed packets (i.e. “sniff” the packets) and, by inference, can use this intercepted information for some malicious purpose. Accordingly, a need exists for a system and method for effectively and efficiently preventing intermediate nodes in a transmission path from intercepting useful amounts of transmitted information.